Multi-Substrate Terpene Synthases: Their Occurrence and Physiological Significance.

Area of Science:

• Plant biochemistry and molecular biology
• Metabolic engineering
• Natural product biosynthesis

Background:

• Terpene synthases (TPS) are key enzymes in plant secondary metabolism, producing a diverse array of terpenes.
• Two main pathways supply TPS substrates: the cytosolic mevalonate-dependent pathway (for sesquiterpenes) and the plastidial 2-C-methyl-D-erythritol-4-phosphate pathway (for other terpenes).
• Recent research indicates some TPS enzymes can utilize substrates from multiple pathways.

Purpose of the Study:

• To review and summarize the current understanding of multi-substrate terpene synthases.
• To highlight the potential underestimation of multi-substrate TPS capabilities in plants.
• To discuss the physiological implications of multi-substrate TPS activity on terpene profiles.

Main Methods:

• Literature review and synthesis of existing research on terpene synthase characterization.
• Analysis of recent advances in gene and enzyme characterization.
• Discussion of metabolic engineering efforts related to terpene biosynthesis.

Main Results:

• Evidence supports the existence of multiple multi-substrate terpene synthases.
• The prevalence and significance of multi-substrate TPS activity may have been considerably underestimated.
• Multi-substrate TPS can lead to altered terpene product profiles when substrate availability changes.

Conclusions:

• Multi-substrate use by terpene synthases is likely a significant factor under physiological conditions.
• Changes in substrate profiles, due to stress or developmental stages, can dramatically modify terpene profiles via multi-substrate TPS.
• Further investigation into multi-substrate TPS is crucial for understanding plant metabolism and terpene diversity.